9. Muscles of the Head



Muscles of the Head


The muscles addressed in this chapter are the muscles of the head. These muscles can be divided into muscles of mastication (chewing), muscles of the scalp, and muscles of facial expression.


Mastication is the act of chewing. Therefore the muscles of mastication are those that attach to and are involved in movement of the mandible at the temporomandibular joints (TMJs). The four major muscles of mastication are the temporalis, masseter, lateral pterygoid, and medial pterygoid.



Muscles of the scalp and facial expression are superficial fascial muscles. The muscles of the scalp are involved in moving the scalp and the ear. Muscles of facial expression can be further subdivided into muscles of the eye, nose, and mouth. The contraction of these muscles is important for displaying emotions. Although some universality of facial expressions that display emotions are certainly apparent, variations are evident from one culture to another. Further, many of these muscles may act in concert with others to add to the spectrum of facial expressions. Some sources state that more than 1800 separate facial expressions can be created with combinations of the muscles of facial expression.


The companion CD at the back of this book allows you to examine the muscles of this body region, layer by layer, and individual muscle palpation technique videos are available in the Chapter 9 folder on the Evolve website.




ATTACHMENTS


Temporalis


Origin (Superior Attachment)



Insertion (Inferior Attachment)




ACTIONS


Both the temporalis and masseter move the mandible at the temporomandibular joints (TMJs).



STABILIZATION

Stabilize the mandible at the TMJs.


INNERVATION



PALPATION


Both the temporalis and masseter are palpated with the client supine.


Temporalis




Masseter




TREATMENT CONSIDERATIONS




ATTACHMENTS


Lateral Pterygoid


Origin (Anterior/Medial Attachment)



Insertion (Posterior/Lateral Attachment)



Medial Pterygoid


Origin (Anterior/Medial/Superior Attachment)



Insertion (Posterior/Lateral/Inferior Attachment)



ACTIONS



Lateral Pterygoid



Medial Pterygoid



STABILIZATION

Stabilizes the mandible at the TMJs.


INNERVATION



PALPATION


Both pterygoids are palpated with the client supine.


Lateral Pterygoid



1. Wearing either a glove or a finger cot, place your palpating finger inside the vestibule of the client’s mouth (between the cheeks and the teeth) and run along the external surfaces of the upper teeth until you reach the back molars. Then press posteriorly and superiorly into a little pocket in the tissue between the gum above the upper teeth and the condyle of the mandible. You will be on the internal surface of the lateral pterygoid (Figure 9-8).


2. Now ask the client to gently either protract the mandible at the TMJs or deviate contralaterally the mandible slowly and carefully (deviate it to the opposite side of the body). Feel for the contraction of the lateral pterygoid (Figure 9-9).


3. Once felt, palpate as much of the lateral pterygoid as possible, from the condyle of the mandible to the inside wall of the mouth (above the gum of the upper teeth).




Medial Pterygoid




TREATMENT CONSIDERATIONS



ent The direction of fibers of the medial pterygoid is essentially identical to the direction of the fibers of the masseter; in fact, these two muscles occupy the same position. The difference is that the masseter is external (superficial) to the mandible, and the medial pterygoid is internal (deep) to the mandible.


ent A tight lateral or medial pterygoid may be involved with dysfunction of the TMJ (TMJ syndrome).


ent The lateral pterygoid functions to protract the mandible and the articular disc of the TMJ. It is important that the mandible and disc protract together when the jaw is opened. Therefore if the contraction of the lateral pterygoid is not precisely coordinated with the other muscles that move the mandible, the articular disc may become jammed between the two bones of the joint and dysfunction of the TMJ (TMJ syndrome) may occur.


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Notes


MUSCLES OF THE HEAD: Muscles of the Scalp


Occipitofrontalis; Temporoparietalis; Auricularis Anterior; Auricularis Posterior; Auricularis Superior


Pronunciation ok-SIP-i-to-fron-TA-lis • TEM-po-ro-pa-RI-i-TAL-is • aw-RIK-u-la-ris an-TEE-ri-or • aw-RIK-u-la-ris pos-TEE-ri-or • aw-RIK-u-la-ris sue-PEE-ri-or




ATTACHMENTS


Occipitofrontalis


Origin (Posterior Attachment)



Insertion (Anterior Attachment)




Note: The galea aponeurotica, a fibrous fascial aponeurosis, is intermediate between the occipital and frontal bellies of the occipitofrontalis.


Temporoparietalis


Origin (Superior Attachment)



Insertion (Inferior Attachment)



Auricularis Group


Auricularis Anterior
  

Origin (Anterior Attachment)



Insertion (Posterior Attachment)



Auricularis Superior
  

Origin (Superior Attachment)



Insertion (Inferior Attachment)



Auricularis Posterior
  

Origin (Posterior Attachment)



Insertion (Anterior Attachment)



ACTIONS


Occipitofrontalis



Temporoparietalis



Auricularis Group



INNERVATION



Aug 22, 2016 | Posted by in MUSCULOSKELETAL MEDICINE | Comments Off on 9. Muscles of the Head

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